A charged-particle-beam lithography apparatus that draws a pattern on a sample by irradiating the sample on a stage with charged particle beams conventionally adjusts the focus of the charged particle beams on a sample face to draw the pattern.
To adjust the focus, a mark provided on the sample face is scanned with the charged particle beams to acquire a signal of reflected electrons while excitation amounts of an objective lens are allocated, and an excitation amount at a time when the rising of the waveform of the signal becomes sharpest is set to the objective lens as a focus during drawing.
In recent years, a charged-particle-beam lithography apparatus of a multibeam system that draws a pattern on a sample using multibeams is adopted from a viewpoint of improving the throughput, or the like.